Fast and efficient identification of pathogens in water, blood serum and other biological fluids is an important yet unsolved issue in medical, forensic and environmental sciences. Conventional plating and culturing are generally used to identify causative bacterial pathogens in clinical environments. While more technologically advanced systems have been developed for specific microorganisms, these methods are generally complex or require sophisticated instrumentation. Plating and culturing is highly accurate, but it is time consuming and requires at least 24 h. Point-of-care treatment decisions are therefore made without having access to crucial microbiological information, often leading to the prescription of a sub-optimal antibiotic. A specific example is the treatment of keflex- or methicillin-resistant S. aureus strains (MRSA) in community-acquired infections that require prompt treatment with either sulfa drugs or vancomycin. Researchers investigated >9000 cases of clinically reported bacterial infections and found that 85-90% were due to only seven pathogens with S. aureus and E. coli being responsible for half of all infections. (B. S. Reisner, G. L. Woods, J. Clin. Microbiol. 1999, 37, 2024-2026.) A simple, and rapid test that could discern the clinically most prevalent pathogens (e.g., bacterial, viral, fungal and others) would be of great value, allowing effective therapeutics against causative pathogens to be administered during the initial point-of-care visit in >85% of all cases. This capability would not only increase the efficacy of therapy, but would also reduce the occurrence of drug-resistant bacteria arising from inefficient antibiotics.
Likewise, the detection of bacteria and other pathogens plays a crucial role in environmental and food safety. For example, E. coli 0157:H7 is a world-wide cause of foodborne illness which is responsible for more than 2000 hospitalizations and 60 deaths directly related to the corresponding bacterial infection each year in the United States, while the outbreak in Japan in 1996 resulted in 10000 infections and 11 deaths. (P. D. Frenzen, A. Drake, F. J. Angulo, J. Food Prot. 2005, 68, 2623-2630; M. D. Disney, J. Zheng, T. M. Swager, P. H. Seeberger, J. Am. Chem. Soc. 2004, 126, 13343-13346.) It has been demonstrated that the major outbreaks are associated with the contamination of unpasteurized juice, vegetables, and water, etc. (P. S. Mead, L. Slutsker, V. Dietz, L. F. McCaig, J. S. Bresee, C. Shapiro, P. M. Griffin, R. V. Tauxe, Emerg. Infect. Dis. 1999, 5, 607-625.) However, testing food for contamination before consumption is often absent due to the complex and/or lengthy analysis protocols.